Train-control system



W. W. MACFAHLANE. 4 TRAIN CONTROL SYSTEM. APPLICATION FILED IIIAII. Is. 1919.

Patmfw Dec. 28, 192i?.

present instance WILLA'M W. MACFARLANE, OF ELKINS PARK, PENNSYLVANJIA.

TRAIN-CONTROL SYSTEM.

Specication of Letters Iatenit. i filtrante@ Dec, 28, 1920.

Application lled March 19, 1919. Serial No. 283,595.

called overbleeding of the train pipe, that4 being an object ot' the invention. l

In the accompanying drawing the inven tion is disclosed in a concrete and preferred forni in which Figure 1 is a diagrammatic view of a system embodying the invention with parts shown in section.

Fig. 2 is a vertical sectional view in line 2 through the piston rod shown in Fig. 1.

Fig. 3 is a detail View ot the fluid pressure system `controlled circuit breaker.

A fluid pressure brake system is indicated by the train pipe 1 associated with which is a brake valve 2 normally in an inopera tive position to hold pipe 1 closed and which when opened serves to reduce pressure in said pipe. The means for actuating the brake valve may vary widely, but in the take the following torm: 3 is a cylinder divided by means ot partition'4 into a lower and an upper compartment respectively indicated at 5 and 6. 7 is a piston rod extending through a stuffing box in4 partition 4 and projecting out through the upper end of cylinder 5% to a point adjacent to actuating lever 8 of the brake valve. Carried by rod 7 are two pistons f) and 10. the former at thelower end of compartment end of compartment 6-when the parts are in their normal position, a spring 11 acting to urge the parts into such position. T o permit air to escape trom onel side ot piston 10 to the other, a bypass 12 is provided; and an orifice 13 is provided near thc top of the lower compartment to allow piston 9 to risc without compressing the air within said lower compartment. A pipe 14 extends from"the train pipe to a casing .15, and a pipe lI6 connects said casing with thc lower end of lower compartment Casing 15 has a valve 17 at its upper end and valve 18 at its lower end. said valves being connected by valve stem 19 and being soar- 5 and the latter at the lower another ranged that when valve 17 is closed valve 18 is open and vice versa.

2O is an electro-magnetic device here shown as a solenoid the core of which is connected to a lever 21 pivoted at 22 in a stationary bearing 23, said lever 21 engag ing with one end of a second lever 24 also pivoted on 23 whose other end engages lower end of valve ste1n19. .It will be seen that so long as magnet 20 is energized, valve 17 is closed and 18 is open. Consequently, no

air can pass from train pipe 1 to lower compartment 5 and spring 11 is therefore ef-` fective to hold pistons 9 and 10 in their lower-most position and brake valve 2 will be closed or inoperative and no reduction in the train pipe will take place. It, however, 20 -is denergized, valve 18 will close and 17 will open thereby permitting air to pass train pipe 1 to lower compartment 5 beneath piston 9. As the air must overcome the action of spring 11, upward movement ot piston 9 and piston rod 7 will be retarded, but, when sufcient pressure has been built up beneath piston 9, piston rod 7 will rise and will open brake valve 2 by raising actuating means 8.v The reason for delaying the action of the device is to admit of momentary deinergization of magnet 20 without operating brake valve 2. Vhen magnet 20 is renergized, valve 17 will be closed and valve 18 i 'ill be opened. the action of spring 11 restoring the parts to their original position and the air beneath piston 9 escaping past valve 18.

Magnet 20 is included in a circuit consisting ot conductors 25, 26 and 27 and battery 28. This circuit is normally held' closed by circuit breaker 29 which is an armature controlled by relay 30,- and the latter may have its own circuit under control ot coil 31 which is a device responsive to changes in traflic conditions. The details of device 31 need not be described since it forms no part ot the present invention. Suffice it to say, that so long as trailic conditions are sate, the circuit energizing magnet 20 will remain closed and brake valve 2 will be inoperative; but when traffic conditions change to denote caution or danger, relay il() will be dcincrgized, thereby rupturing the circuit including magnet 20 and 'rendering brake valve 2 operative -to canse reduction in pressure in pipe 1. To prevent. overblccfling of pipe 1, provision is made whereby when a certain reduction in pressure has been effected, magnet 2 0 will vbe energized regardless of tralic conditions or regardless of position of circuit breaker' 29, said magnet. being again denergized 5 when pressure has again been built up above ductor '3,4 to conductor 26. An adjustable stop or Contact member 35 is properly insulated from hand 33 and is connected by laconductor 36 to conductor 27. If contact 135 is set, say at 12% lbs. pressure indicating position, then when magnet is denerized by a change in -traiic conditions a reuction in pressure of pipe 1 will be effected, this lreduction continuing until movable contact 33 encounters contact 35 when a circuit is `closed through battery 28 and magnet 20 thereby. closing brake valve 2. As soon as pressure is built up again, contact 33 will move away from contact 35 and magnet 20 will be denergized assuming that relay 3()l is still denergized; but if traiiic conditions have meanwhile changed and armature 29 has been picked up then pressure will continue to be built up until the usual maximum employed in existing devices has been attained.

I cla-im; l 1. Train control means comprising: ailuid pressure brake system, a brake valve included in said system for reducing pressure therein, electro-magnetic means which when energized holds the brake valve inoperative, a normally closed circuit normally energizing the electro-magnetic means, means for rupturingf-the closed circuit, and means for automatically closing the circuit to lreenergize the electro-magnetic means when a predeterminem reduction in the fluid pres-f sure system has been eli'ected.

2. Tram control means comprising: a fluid pressure brake system, a brake valve includedl in said system for reducing pressure therein, electro-magnetic means which when energized holds the brake valve' inoperative, a normally closed circuit normally energizing the electro-magnetic means, means for rupturing the closed circuit at one point, and means for automati-V cally closing the circuit at another point to renergize the electro-magnetic means when a predetermined reduction in the fluid pressuresystem has been elfected.

3. Train vcontrol means comprising: a Huid pressure brake system, abrake valve included ingsaid system for reducing pres sure therein, a normally closed circuit normally holdin the brake valve inoperative,

.traffic contro led means for rupturing said holding the brake valve inoperative, a'traliic controlled circuit breaker in 'said circuit, and

`a circuit breaker controlled by'fluctuation of pressure in the fluid pressure brake system also included in said circuit.

5. Train control means comprising: a fluid pressurebrake system, a brake v alve included in said systemy for reducing pressure therein, .a normally'closed circuit normally holding the brakevalve inoperative, a circuit .breaker holding-.the circuit open at one point so long as a given minimum of pressure exists in the brake system and closing said circuit upon a decrease in pres- 'sure below the given' minimum, and aA circuit brea-ker-for opening and closing the circuit at another point 1n accordance with traiic conditions, the circuit being com plete when,either circuit breaker is in its closed position.

Signed at Philadelphia, l Philadelphia and .State of this Gthda of March, 1919.

`YVI LAM .W. M ACFARLANE.

in the county of y Pennsylvania, 

